Projects per year
Abstract
We previously used a single nucleotide polymorphism (SNP) in the CHRNA5-A3-B4 gene cluster associated with heaviness of smoking within smokers to confirm the causal effect of smoking in reducing body mass index (BMI) in a Mendelian randomisation analysis. While seeking to extend these findings in a larger sample we found that this SNP is associated with 0.74% lower body mass index (BMI) per minor allele in current smokers (95% CI -0.97 to -0.51, P = 2.00×10-10), but also unexpectedly found that it was associated with 0.35% higher BMI in never smokers (95% CI +0.18 to +0.52, P = 6.38×10-5). An interaction test confirmed that these estimates differed from each other (P = 4.95×10-13). This difference in effects suggests the variant influences BMI both via pathways unrelated to smoking, and via the weight-reducing effects of smoking. It would therefore be essentially undetectable in an unstratified genome-wide association study of BMI, given the opposite association with BMI in never and current smokers. This demonstrates that novel associations may be obscured by hidden population sub-structure. Stratification on well-characterized environmental factors known to impact on health outcomes may therefore reveal novel genetic associations.
Original language | English |
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Pages (from-to) | e1004799 |
Journal | PLoS Genetics |
Volume | 10 |
Issue number | 12 |
DOIs | |
Publication status | Published - 4 Dec 2014 |
Structured keywords
- Brain and Behaviour
- Tobacco and Alcohol
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Dive into the research topics of 'Stratification by smoking status reveals an association of CHRNA5-A3-B4 genotype with body mass index in never smokers'. Together they form a unique fingerprint.Projects
- 3 Finished
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Using Mendelian Randomisation to Establish the Causal Role of Cigarette Smoking in Anxiety and Depression
1/11/12 → 1/11/13
Project: Research
Profiles
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Professor Marcus R Munafo
- School of Psychological Science - Professor of Biological Psychology and MRC Investigator
- Senior Team - Associate Pro Vice-Chancellor - Research Culture
- Bristol Population Health Science Institute
- MRC Integrative Epidemiology Unit
- Bristol Neuroscience
Person: Academic , Member